Current therapy delivery catheters are typically made to be as small as possible for easy passage into a body tissue or cavity. A therapy may be injected through a catheter lumen and the catheter is then withdrawn from the tissue or body cavity. If the catheter is too large for the passageway, it may cause trauma to the surrounding tissue and make navigation into and through body cavities a challenge. Therefore, it is desirable to have a catheter of a small lumen size which is capable of delivering a therapy without causing trauma to the tissue along the passageway to the desired delivery site.
In the past, instruments for the purpose of injection of a fluid have been used in conjunction with endoscopes. For example, EP0818208A2 describes a working channel of an endoscope being used to pass a catheter and guidewire for this purpose.
Catheters with expandable sections at a distal end are well known in the prior art for the purpose of tissue expansion or dilation as in U.S. Pat. No. 8,414,473B2, and for the purpose of hydrogel delivery as in U.S. Pat. No. 6,524,274, for example. U.S. Pat. No. 6,524,274, however, teaches release of a hydrogel from an outer surface upon contact with a triggering agent, rather than hydrogel delivery through a catheter as in the present invention.
Despite the approaches discussed above, there is still a need for a catheter conduit with a diameter large enough for injection of a viscous hydrogel fluid into an anatomical region of interest, for example into a sinus cavity.
In addition, there is a need for such a conduit to be provided with an expandable section at a distal end such that a thicker, more viscous fluid is able to elute through various pores or holes in an outer surface of the expandable section to provide a more even distribution of a therapy to the surrounding anatomical structures.
There is also a need for such a catheter conduit to be insertable into an anatomical region of interest provided along a path consistent with the shaft of an endoscope such that visualization of the anatomical space for therapy delivery is possible. In sinus procedures, for example, this path would be a non-straight line path for targeted delivery into a sinus cavity.